Symptoms of autism spectrum disorder (ASD) often surface in toddlers between 12 and 18 months. Now, new research finds that by the time a reliable diagnosis can be made (usually after 24 months), toddlers affected by autism are already displaying emotional vulnerabilities which may predict comorbid emotional and behavioral conditions common in older kids with ASD.
The study is published in the Journal of the American Academy of Child and Adolescent Psychiatry (JAACAP).
The findings reveal a surprising and complex emotional landscape in toddlers with ASD. Specifically, ASD toddlers tend to display more anger and frustration but less fear in response to natural situations. The researchers also found that the capacity to experience joy appears intact in the early stages of the disorder.
“ASD onsets in most cases within the first two years of life and affects approximately 1 in 59 children,” said lead authors Suzanne Macari and Katarzyna Chawarska, Ph.D., at the Child Study Center at the Yale School of Medicine.
“This study documents, for the first time, that at the earliest age when the disorder can be reliably diagnosed, toddlers with ASD already display emotional vulnerabilities signaling risk for co-morbid affective and behavioral problems.”
The findings are based on a study of emotional development in toddlers referred for a differential diagnosis of ASD in the Northeastern United States and includes 43 toddlers with ASD and 56 non-ASD controls.
The researchers recruited 21-month old participants between December 2013 and March 2017. Using several approaches, the researchers examined the intensity of the toddlersâ€™ emotional responses across vocal and facial channels to natural situations aimed to elicit anger, fear, and joy.
“The vulnerabilities are unrelated to autism symptoms and thus, contribute independently to the development of complex and highly heterogenous autism phenotypes,” said the authors.
“In addition to targeting social and communication concerns, clinicians should also focus on assessing and treating affective symptoms in young children with ASD with the hope of ameliorating the severity of comorbid disorders so common in ASD.”
For example, the researchers found that when a desired object is put out of reach of the toddler, toddlers with ASD displayed elevated levels of anger and frustration. However, when faced with new and potentially threatening objects, ASD toddlers showed less fear than did the comparison groups.
While an elevated anger response may challenge the developing emotion regulation system, the weakened fear response suggests an abnormal assessment of threat and risk.
In addition, although there is a prevailing notion that ASD children do not experience joy as much as other children, the study found that levels of joy in response to playful situations was comparable in toddlers with ASD and the control groups. This suggests that in the early stages of the disorder, the capacity to experience joy is still present.
Harnessing this intact emotional ability for therapeutic purposes is essential as activation of positive emotions promotes learning and exploration and counters stress. The study provides strong motivation for investigating early emotional development in ASD and its role in emergence of autism.